PowerPoint Presentation

NATIONAL ACHIEVEMENT TEST REVIEW in earth science(earths interior)MYLENE ROMERO NEVIAR- Facilitator

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What to expect: This slides will help you visualize and understand the composition and structure of the Earths interior.

PRE-ASSESSMENT1. An S-wave shadow zone is formed as seismic waves travel through the earths body. Which of the following statements does this S-wave shadow zone indicate?A. The inner core is liquidB. The inner core is solidC. The mantle is solidD. The outer core is liquid.

PRE-ASSESSMENT2. Why are there no P-waves or S-waves shadow ?A. P-waves are absorbed and S-waves are refracted by Earths outer core.B. P-waves are refracted and S-waves are absorbs by Earths outer coreC. Both the P-waves and S waves are refracted by Earths outer core.D. Both the P-waves and S waves are absorbs by Earths outer core.

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PRE-ASSESSMENT3. What makes up the lithosphere?A. Continental crust

B. Crust and the Upper mantle

C. Oceanic Crust and the upper mantle.

D. Upper mantle

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PRE-ASSESSMENT4. Miners dig into the Earth in search for precious rocks and minerals. In which layer is the deepest explorations made by miners?A. Crust

B. Inner Core

C. Mantle D. Outer Core

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PRE-ASSESSMENT5. How do you compare the densities of the Earths crust, mantle and core?A. The mantle is less dense than the core but denser than the crust.B. The mantle is less dense than both core and the crust.C. The mantle is denser than the core but less dense than the crustD. The mantle is denser than both the core and the crust.

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PRE-ASSESSMENT6. The movement of the lithospheric plates is facilitated by a soft, weak and plastic-like layer. Which of the following layers is described in the statement?A. Asthenosphere

B. Atmosphere

C. Lithosphere D. Mantle

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PRE-ASSESSMENT7. Alfred Wegener is a German scientist who hypothesized that the earth was once made up of a single large landmass called Pangaea. Which of the following theories did Wegener propose?A. Continental Drift Theory B. Continental Shift TheoryC. Plate TectonicsD. Seafloor Spreading Theory

PRE-ASSESSMENT8. If you are a cartographer, what will give you an idea that the continents were once joined?A. Ocean depth B. Position of the South poleC. Shape of the continentD. Size of the Atlantic Ocean

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PRE-ASSESSMENT9. Which observation was NOT instrumental in formulating the Hypothesis of seafloor spreading?A. Depth of the Ocean

B. Identifying the location of glacial deposits

C. Magnetization of the Oceanic Crust D. Thickness of Sea floor sediments

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PRE-ASSESSMENT10. As a new seafloor is formed at the mid-ocean ridge, the old seafloor farthest from the ridge is destroyed. Which of the stated processes describes how the oceanic crust plunges into the Earth and destroyed at the mantle?ConvectionConstructionDiversionSubduction

PRE-ASSESSMENT11. In 1912, Alfred Wegener proposed a theory that the earth is once a single landmass. What is the name of the Mesozoic supercontinent that consisted of all of the present continent?EurasiaLaurasiaPangaeaGondwanaland

PRE-ASSESSMENT12. Who were the two scientists who proposed the theory of seafloor spreading in the early 1960s?Charles Darwin & James HuttonHarry Hess & Robert DietzJohn Butler & Arthur SmiteF. Vine and D. Mathews

PRE-ASSESSMENT13. If the Atlantic Ocean is widening at a rate of 3 cm per year, How far (in Kilometers) will it spread in a million years.3 kilometers30 kilometers300 kilometers3000 kilometers

PRE-ASSESSMENT14. Which of the following increases with distance from a mid-ocean ridge?The age of oceanic lithosphereThe thickness of the lithosphereThe depth to the seafloorAll of the above

PRE-ASSESSMENT15. If all the inner layers of the Earth are firm solid, what could have happened to PangaeaIt remained as a supercontinentIt would have become as it is todayIt would have slowly disappeared in the oceanIt would have stretched and covered the whole world.

What are seismic waves?These are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and recorded on seismographs.Full of energyVery fast moving (Speed in km/s)

Types of Seismic WaveSurface waves

Body Waves

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Surface Waves(L-Waves)Moves along the earths surface.They move up and down. Love WavesRaleigh Waves

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These waves are a type of surface acoustic wave that travel on solidsRayleigh Waves

Named for John William Strutt, Lord Rayleigh, who mathematically predicted the existence of this kind of wave in 1885.Rolls along the ground just like a wave rolls across a lake or an ocean. Because it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is moving.Most of the shaking felt from an earthquake is due to the Rayleigh wave, which can be much larger than the other waves.

Rayleigh Wave

Love Wavenamed after A.E.H. Love, a British mathematician who worked out the mathematical model for this kind of wave in 1911.faster than Rayleigh waveit moves the ground in a side-to-side horizontal motion, like that of a snakes causing the ground to twistcause the most damage to structures during an earthquake.

Love Wave

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Surface Waves(L-Waves)

Land waves move along the surface of the earth and cause it to move up and down like something bobbing on the surface of the ocean.

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Surface Waves(L-Waves)

Land waves only move along the surface of the earth. Their speeds vary depending on the material, rock or soil, forming the surface. These waves cause the surface to move up and down. These are the waves that cause The to buildings and other structures during an earthquake.

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Body WavesPrimary WavesSecondary Wavespush and pull side to side

Body wavescan travel through the Earths inner layersthey are used by scientists to study the Earths interiorhigher frequency than the surface waves

P-waves (Primary)compressional waves, travel by particles vibrating parallel to the direction the wave travel move backward and forward as they are compressed and expandedthey travel through solids, liquids and gases

P-waves (Primary)is a pulse energy that travels quickly through the Earth and through liquidstravels faster than the S-waveit reaches a detector first

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Primary Waves

Primary waves are compression waves. They push and pull the rocks of the earth's surface. They can move through solid rock and fluids like water or the liquid core layers of the earth And first to 'arrive' at a seismic station.

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Primary waves push and pull on the rocks through which they are traveling. This creates a back and forth movement on the Earth's surface. This is just like sound waves pushing and pulling the air. Have you ever heard a big clap of thunder and heard the windows rattle at the same time? The windows rattle because the sound waves were pushing and pulling on the window glass much like P-waves push and pull on rock. Primary Waves

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Secondary Waves

Secondary waves travel slower than primary waves. Also called shear waves "or Transverse Waves. They create a side to side motion in the rocks through which they are traveling.

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Secondary Waves

Unlike the other earthquake waves, S-waves cannot travel through water or the liquid rock of the Earth'score layer. They can Travel through solid only-waves will rock buildings side-to-side.

S-waves (Secondary/Shear)pulse energy that travels slower than a P-wave through Earth and solidsMove as shear or transverse waves, and force the ground to sway from side to side, in rolling motion that shakes the ground back and forth perpendicular to the direction of the waves

Seismic Waves movement

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Seismic Waves

Types of Seismic Waves

Cross section of the Earth as seismic waves travel through it

P waves can travel through liquids while s waves cannot. Based on the figure, the Waves bend due to change in density of the medium. As the depth increases, the density also increases. The idea that the s-waves cannot travel through any liquid medium led seismologists to conclude that the outer core is liquid.

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Remember:P-waves are detected on the other side of the Earth opposite the focus. A shadow zone from 103 to 142 exists from P-wavesSince P-waves are detected until 103, disappear from 103 to 142, then reappear again, something inside the Earth must be bending the P-waves

Remember:existence of a shadow zone, according to German seismologist Beno Gutenberg (u t n bk), could only be explained if the Earth contained a core composed of a material different from that of the mantle causing the bending of the P-wavesTo honor him, mantlecore boundary is called Gutenberg discontinuity

Remember:From the epicenter, S-waves are detected until 103, from that point, S- waves are no longer detectedS-waves do not travel all throughout the Earths bodyknowing the properties and characteristics of S-waves (that it cannot travel through liquids), and with the idea that P-waves are bent to some degree, this portion must be made of liquid, thus the outer core

Remember: 1936, the innermost layer of the Earth was predicted by Inge Lehmann, a Danish seismologistdiscovered a new region of seismic reflection within the coreEarth has a core within a core

Remember: the outer part of the core is liquid based from the production of an S wave shadow and the inner part must be solid with a different density than the rest of the surrounding materialsize of the inner core was accurately calculated through nuclear underground tests conducted in Nevada. echoes from seismic waves provided accurate data in determining its size

OUR HOME PLANET, EARTHOur Earth is about average among the planets in the Solar System, in many respects:largest and most massive of the four terrestrial planets, but smaller and less massive than the four giant, or Jovian, planetsthird in distance from the Sun among the four terrestrial planetshas a moderately dense atmosphere; 90 times less dense than that of Venus but 100 times denser than that of Mars

OUR HOME PLANET, EARTHEarth is also unique in many respects:the only planet with liquid water on its surface.the only one having a significant (21%) proportion of molecular oxygento our best current knowledge, the only planet in the solar system having living organismsthe only terrestrial planet having a moderately strong magnetic fieldthe only terrestrial planet having a large satellite

The Solid Earthgeology -the study of the structure, history, and activity of the solid Earth, including its interactions with the atmosphere, hydrosphere, cryosphere, and biospheresolid Earth contains four major zones: the core (which is divided into inner and outer zones), the (upper and lower) mantle, the asthenosphere, and the lithosphere

The Solid Earththe outer zones is not uniform and fixed over the surface of the Earth, but shows much variability with position and time.The field of plate tectonics deals with this spatial and temporal variability.Geological phenomena such as earthquakes, volcanoes, and continental drift are accounted for by plate tectonics.

The Composition of the Earths Interior

Did you know?The deepest mine in the world, the gold mine in South Africa, reaches a depth of 3.8km.But...You would have to travel more than 1,600 times that distance-over 6000km-to reach the earths center.

The Composition of the Earths Interior

DENSITY AND TEMPERATURE VARIATION IN DEPTH

Crust

The Crust

The Crustthinnest and the outermost layer of the Earth that extends from the surface to about 32 kilometers belowContinentalOceanic

Stanley, 1989, p. 14Continental

Stanley, 1989, p. 14ContinentalRootMohoOceanicLithosphereAsthenosphere

Continentalmainly made up of silicon, oxygen, aluminum, calcium, sodium, and potassiummostly 35-40 kilometersfound under land massesmade of less dense rocks such as granite

Oceanicoceanic crust is around 7-10 kilometers thick which its average thickness is 8 kilometers. found under the ocean floormade of dense rocks such as basalt heavier than the continental crust.

The Crust: Continental

GRANITE -crystalline igneous rock composed primarily of quartz and feldspar.forms from slowly cooling magma that is subjected to extreme pressures deep beneath the earth's.

The Crust: Oceanic

BASALT -volcanic rock forms from lava flows along mid-ocean ridges and also in igneous intrusions such as dikes and sills. Columnar jointing, pictured here at Devil's Tower, Wyoming, occurs when molten basalt cracks as it cools, producing separate, polygonal fractures on the surface of the rock.

Elements in the Crust

Moho DiscontinuityWhile studying the speed of earthquake waves, Croatian geophysicist Andrija Mohorovii discovers a boundary between Earth's crust and mantle, which becomes known as the Mohorovii, or Moho, Discontinuity.

Mantle

The MantleBeneath the crust is the mantleextends to about 2900 kilometers from the Earths surfaceabout 80% of the Earths total volume about 68% of its total mass mainly made up of silicate rocksand contrary to common belief, is solid, since both S-waves and P-waves pass through it

The Mantlemostly made of the elements silicon, oxygen, iron and magnesiumlower part of the mantle consists of more iron than the upper partlower mantle is denser than the upper portiontemperature and the pressure increase with depthhigh temperature and pressure in the mantle allows the solid rock to flow slowly

Remember:The ability of the asthenosphere to flow slowly is termed as plasticity. crust and the uppermost part of the mantle form a relatively cool, outermost rigid shell called lithosphere (Gk.lithos means stone) and is about 50 to 100 kilometers thick

Remember:Beneath the lithosphere lies the soft, weak layer known as the asthenosphere (Gk. asthenes means weak) made of hot molten material, about 300 800o Cupper 150 kilometers has a temperature enough to facilitate a small amount of melting, and make it capable to flowfacilitates the movement of the lithospheric plateslithosphere, with the continents on top of it, is being carried by the flowing asthenosphere.

Layers

Core

The Core2000-5000o Ccore is subdivided into two layers: the inner the outer core.

Outer Core2900 kilometers below the Earths surface2250 kilometers thick made up of iron and nickeltemperature reaches up to 2000oC at this very high temperature, iron and nickel melt

Outer CoreAside from seismic data analysis, the Earths magnetic field strengthens the idea that the Earths outer core is molten/liquidmainly made up of iron and nickel moving around the solid inner core, creating Earths magnetism

The Inner Coremade up of solid iron and nickel and has a radius of 1300 kilometersabout 5000oCextreme temperature could have molten the iron and nickel but it is believed to have solidified as a result of pressure freezing, which is common to liquids subjected under tremendous pressure

The Inner CoreAside from the fact that the Earth has a magnetic field and that it must be iron or other materials which are magnetic in nature, the inner core must have a density that is about 14 times that of water. Average crustal rocks with densities 2.8 times that of water could not have the density calculated for the core. So iron, which is three times denser than crustal rocks, meets the required density.

Clues that the inner core and the outer core are made up of ironIron and nickel are both dense and magnetic.overall density of the earth is much higher than the density of the rocks in the crustsuggests that the inside must be made up of something denser than rocks

Clues that the inner core and the outer core are made up of ironMeteorite analysis have revealed that the most common type is chondrite. Chondrite contains iron, silicon, magnesium and oxygen; some contains nickel.The whole earth and the meteorite roughly have the same density, thus the Earths mantle rock and a meteorite minus its iron, have the same density.

The core is important as..It is thought to be the main reason behind the driving forces of convective currents in Mantle.It is responsible to maintain Earths magnetic field.

If the core stops spinning, the magnetic field will collapse resulting in destruction of Earths surface by violent solar storms.

Thank You.